Javier Waitzel, Developer in Buenos Aires, Argentina
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Javier Waitzel

Verified Expert  in Engineering

Software Developer

Buenos Aires, Argentina
Toptal Member Since
April 9, 2014

Javier is a top engineer and entrepreneur passionate about new technologies and software development. He has experience in mobile application design and development, and he's worked extensively with multidisciplinary teams, bringing innovative ideas to every project.


Swift, SwiftUI, Python
Objective-C, iOS, Auto Layout, Twitter SDK, YouTube API, Git, REST, HTTPS...
Facebook SDK, iOS, Objective-C, Swift




Preferred Environment

Git, C#, Unity, MacOS, iOS, Objective-C, Xcode, UIKit, Swift, SwiftUI

The most amazing...

...thing I've built is an Arduino-server iOS project to unlock doors that works smoothly when nearby.

Work Experience

iOS Engineer

2023 - 2023
  • Created an iOS application with SwiftUI and WebSockets.
  • Developed the back end using Python and FastAPI and deployed the server on a GPU on-demand service.
  • Integrated Diffusers library for image generation with SD1.5.
Technologies: Swift, SwiftUI, Python

iOS UI Developer

2015 - 2019
  • Developed an artist-based app, aggregating content from many sources like YouTube, Twitter, and Instagram.
  • Designed and developed features in Objective-C. Migrated to Swift and UIKit and then SwiftUI. Created frameworks for multiple apps to use.
  • Implemented a video editor to create content using AVKit and AVFoundation. Worked on the music library integration. Contributed to the creation of gifs, stickers, etc.
Technologies: Objective-C, iOS, Auto Layout, Twitter SDK, YouTube API, Git, REST, HTTPS, AVKit, AVFoundation, SwiftUI, Swift, APIs

iOS Engineer

2015 - 2015
  • Created an iOS app to manage all your fantasy teams from different providers in one place.
  • Supported the login using different third-party services (Facebook, Twitter, and Google).
  • Implemented views with code using Masonry (the Auto Layout framework) supporting all iPhone screen sizes.
  • Collaborated with the design team and created reusable views to create a consistent UI.
  • Supported continuous integration, code coverage, crash reports, and analytics frameworks.
Technologies: Facebook SDK, iOS, Objective-C, Swift

iOS Engineer

2015 - 2015
Ceevoo (via Toptal)
  • Built an app for discovering nearby users using iBeacons (BLE).
  • Enhanced "Universal" app experience for iOS using Size Classes.
  • Used Core Bluetooth and Core Location simultaneously for advertising and discovering users.
  • Implemented Parse integration with a local data store and push notifications.
  • Created a framework for discovering users even if the app is closed.
Technologies: Bluetooth LE, Parse, Swift

iOS Engineer

2014 - 2014
uSuit (via Toptal)
  • Created a 3D High-Poly model viewer app for iOS (Universal).
  • Implemented Dropbox integration.
  • Implemented SceneKit and UIKit integration.
  • Implemented mesh customization in real-time.
  • Created synchronized local storage for offline use.
Technologies: SQLite, Objective-C, Swift

iOS Engineer

2014 - 2014
reTXT (via Toptal)
  • Created a text messaging iOS app. Worked with a team of 3 iOS developers.
  • Implemented Apache Thrift integration.
  • Built a custom SQLite local database.
  • Implemented multimedia messages.
  • Achieved complex animations using Core Animation and Auto Layout.
  • Built an API basis to use in all mobile clients.
Technologies: Core Animation, Apache Thrift, SQLite, Objective-C, iOS

Co-founder | Developer

2010 - 2014
Esqulilax Games
  • Migrated several Objective-C/Cocos2D projects to Unity.
  • Created an OpenGL-based graphics engine supporting 2D and 3D rendering. Integrated a physics engine (Box2D) using C++. Modified the code to project requirements.
  • Designed a custom-level creation tool for the app Climber Brothers.
  • Developed several iOS games (Climber Brothers, Battle Rush, Chinchon, and Escoba de 15).
  • Created an OBJ (3D models) loader and parser for 3D-mesh rendering.
  • Developed the AI for card games featuring a variable level of skill.
  • Added support for sharing content on social networks in all of the company's games.
  • Incorporated SVG support for curve creation and terrain design. Created a smoothing algorithm using SVG curves and approximation.
  • Designed and implemented a PVP (Player versus Player) multiplayer environment for a battle game.
  • Developed a server-client framework to display animations simultaneously on different devices.
Technologies: C#, Unity, Objective-C, OpenGL ES, OS X, iOS

Software Engineer

2013 - 2013
iKey SRL
  • Developed an iOS and iPad app for final users and admins.
  • Developed the Arduino software for interacting with the iOS app and the server.
  • Created and deployed the hardware solution for the project using Arduino.
  • Integrated two incompatible Arduino shells using a master-slave model.
  • Developed several functionalities in the back-end using PHP and SQL.
  • Integrated Bluetooth low-energy allowing proximity opening for doors.
  • Developed an offline solution and an on-demand synchronization with the server.
Technologies: Bluetooth LE, SQL, Objective-C, PHP, Arduino

iOS Developer

2012 - 2012
  • Developed the app, "Vale Puerto", for showing company port facilities in Argentina.
  • Created the app, "Vale", for displaying company facilities in Argentina.
  • Supported image and video display via AVFoundation.
  • Designed a custom map interface showing different spots in the VALE facilities.
  • Designed a plist-based file for storing and loading map points and information.
  • Implemented support for efficient scrolling around the "Vale" app.
Technologies: Objective-C, iOS

iOS Developer

2012 - 2012
Portegno Apps
  • Created the "Crazy Hairstyle Studio" app.
  • Developed a base framework for editing hairstyles in a realistic hairstyle salon app.
  • Added features for camera support, photo editing, and screenshot export to a game.
  • Created a Photoshop script for exporting hairstyles and loading them into the app.
  • Integrated OpenGL and UIView successfully improving general performance.
  • Added support for real-time image editing by rendering images to textures.
  • Created an anchor and multi-point manipulation system for displayed objects.
  • Built a multi-shading tool for blurring, coloring, and efficient rendering of images.
Technologies: XML, Objective-C, OpenGL ES, iOS

iOS Developer

2011 - 2012
Webetico SNC
  • Created a CRM app allowing customers to place orders online and offline.
  • Created a multi-language app for a museum displaying information about museum exhibits.
  • Integrated image synchronization on demand.
  • Developed a framework for synchronizing local data with server data.
  • Designed and implemented a custom grid for displaying data.
  • Supported communication with an AS400 for an iOS app.
  • Supported multithreaded loading of images to display in a catalogue.
  • Created a trivia game that allowed prospective customers to enter their contact information.
Technologies: SQL, iOS, Objective-C

Climber Brothers

An iOS rope physics puzzle game with 4.5/5 stars review.
Free version: https://itunes.apple.com/us/app/climber-brothers-lite/id452800570?l=es&ls=1&mt=8

Battle Rush

An infinite multiplayer PVP runner game.

Crazy Hair Studio

A realistic hairstyle simulator.


A Spanish card game for iOS.

Escoba de 15

A Spanish card game with single and multiplayer features.


A jewelry catalogue iPad application for Cielo Venezia.

Award for Esquilax Games

Our company was choosen from 200 indie game companies around the world for the program Chartboost University: Boot Camp and for the GDC (Game Developers Conference).
2009 - 2013

Bachelor's Degree in Software Engineering

Universidad Tecnológica Nacional - Buenos Aires, Argentina


Parse SDK, Flurry, AVKit, Facebook iOS SDK, AdColony, Dropbox API, Twitter SDK, OpenGL ES, Core Animation, Facebook SDK, SBJson, YouTube API


Adobe Photoshop, TestFlight, Xcode, Git, 3ds Max, Adobe Illustrator, Cinema 4D, Microsoft Visual Studio, MAMP, Auto Layout


AFNetworking, iOS SDK, Cocoa, Cocoa Touch, SwiftUI, UIKit, Unity, Unity3D, Core Location, Core Bluetooth, Apache Thrift


Swift, Objective-C, Java, C++, C#, XML, PHP, C, SQL, Python


Object-oriented Programming (OOP), Agile Software Development, XP, Model View Controller (MVC), Continuous Integration (CI), REST


iOS, Dropbox, Mapbox, Arduino, OS X, Bluetooth LE, Parse, MacOS, Windows




Game Development, Bluetooth, Games, APIs, User Interface (UI), Game Design, HTTPS, AVFoundation

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